Preparation and Characterization of Activated Carbon Based on Wood (Acacia auriculeaformis, Côte d’Ivoire)

Abstract

The objective of this work is to prepare one of the best activated carbon (CA) based on wood (Acacia auriculeaformis). The chemical activation method was used for varying the chemical agent namely phosphoric acid H3PO4 (CAA), sodium hydroxide NaOH (CAB), and sodium chloride NaCl (CAS). The physico-chemical analysis of the three activated carbons indicated that, under the conditions of preparation, the activated carbons possess activation efficiencies lower than 50% (41.81% for CAA, 26.25% for CAB and 48.87% for CAS), low ash content (CAA: 5.00%, CAB: 14.90 and CAS: 6.60%) and iodine values ranging from 190.35 mg/g to 380.71 mg/g, suggesting that the good quality of the prepared activated carbon. The surface functional groups using Boehm test and the zero point charge (pHZPC) methods confirmed the acidic, basic and neutral character for CAA, CAB and CAS respectively (CAA: pHZPC = 4.8, CAB: pHZPC = 8.2, CAS: pHZPC = 6.8). The surface specific areas were determined through the liquid phase adsorption of acetic acid and methylene blue using the Langmuir method and BET analysis. Also, the porosity was determined. The BET surface areas of CAA, CAB and CAS were respectively 561.60 m2/g, 265.00 m2/g and 395.40 m2/g. The influence of chemical activation agent on pores formation was confirmed by scanning electron microscopic (SEM) analysis. CAA was selected as the best activated carbon because of its good surface area and good pore volume compared to those found in the literature. Therefore, its application as an adsorbent for effluents treatment could be explored. In addition, the best activating agent for coal from Acacia auriculeaformis was found to be phosphoric acid.